Immunochromatography is a well established testing method used to test for the presence or absence of an antigen (usually a biological protein) in a biological sample. The sample is supplied to a lateral flow test device and flows by capillary action through a label-holding substance which contains a soluble and labelled antibody specific to a particular antigen. If that antigen is present in the sample, an antigen-antibody (labelled) complex is formed which then continues to permeate by capillary action through the device to a test site where the complex is captured by a second antibody attached to the test site. This results in an increase in the density of captured antigen-antibody (labelled) complexes at the test site which results in a visible mark (usually a line) on the test site indicating the presence of the antigen in the sample.
Prior to carrying out the lateral flow test, the test sample must be obtained. This is often an invasive process, particularly if the fluid sample comprises nasal discharge, for example, requiring insertion of a foreign object into a body cavity to obtain the sample.
To obtain nasal discharge (e.g., mucus), a ‘nasopharyngeal aspirate’ is routinely performed, which involves passing a thin plastic tube into the nose and suctioning discharge from within the nose. Alternatively, a ‘Q-tip’ or ‘cotton bud’ is inserted via the nose into the nasopharynx and then withdrawn with a small sample of discharge. These methods are at present widespread in sampling nasal discharge for testing and are not without risks, including trauma to the nasopharyngeal mucosa and potential injury to the cribriform plate which forms the roof of the nose, separating it from the brain. Additionally, the accuracy of these test methods are highly dependent upon attaining a quality sample and therefore the skill of the person acquiring the sample. As a result these methods are carried out by trained health personnel and the associated devices are not necessarily available for sale direct to the public.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.